What happens to hydrogen-ion concentration when water is added to an acidic solution?
Answer and explanation
Correct answer: The number of hydrogen ions per unit volume decreases, so acidity becomes lower
Dilution increases the total volume while the original amount of dissolved acid is distributed through that larger volume. Consequently, the hydrogen-ion concentration, [H⁺] or more precisely [H₃O⁺] in water, decreases. Since pH = −log[H⁺], the pH rises and the solution becomes less acidic, although it does not necessarily become basic. Thus option A is correct; dilution does not destroy all ions or automatically produce a basic solution.
Frequently asked questions
What is the correct answer to this question?
The number of hydrogen ions per unit volume decreases, so acidity becomes lower
Why is this the correct answer?
Dilution increases the total volume while the original amount of dissolved acid is distributed through that larger volume. Consequently, the hydrogen-ion concentration, [H⁺] or more precisely [H₃O⁺] in water, decreases. Since pH = −log[H⁺], the pH rises and the solution becomes less acidic, although it does not necessarily become basic. Thus option A is correct; dilution does not destroy all ions or automatically produce a basic solution.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
